Comparing collaborative problem solving in virtual reality and desktop computer display environments

https://www.ester.ee/record=b5160211*es

Refining Pedogenic Carbonate Proxies for Improved Reconstructions of Past Terrestrial Environmental Conditions.

Continental paleoclimate records provide a means to assess regional climate variability through time and assess how the evolution of the terrestrial biosphere has driven and responded to environmental change. Fossil soils (paleosols) are a particularly useful paleoclimate archive, because they are widely distributed throughout the geologic record. Carbonate clumped isotope paleothermometry is an exciting new proxy for paleosols, as it has the potential to assess temperature seasonality. Yet the processes underlying soil carbonate formation and clumped isotope temperature resetting must be further understood before this proxy can be effectively applied. My dissertation centers on improving understanding of the processes controlling soil carbonate formation and critically evaluating the potential resetting of clumped isotope carbonate data from terrestrial deposits. In Chapter 2, I use modern samples to explore seasonal biases associated with the clumped isotope composition of soil carbonate. The results demonstrate that soil carbonate can form at or below mean annual temperatures. The cold nature of these results is explained by the annual timing of soil water depletion, which is driven by patterns of seasonal precipitation and evapotranspiration. In Chapter 3, modern soil environmental data are compiled to examine how soil temperatures relate to surface air temperatures and to quantify systematic biases that will affect paleosol proxies. Seasonal fluctuations in soil moisture are used to predict the seasonal timing of pedogenic carbonate formation. Soil temperature data indicate that pedogenic carbonate is more likely to record warm season bias relative to mean annual air temperature. In Chapter 4, I use clumped isotope and organic biomarker analyses on the 1.1 Ga Nonesuch Formation to explore how easily the clumped isotope thermometer can be reset on geologic samples and to evaluate the performance of new solid-state reordering models. Using a solid-state reordering model, I illustrate that the synsedimentary and early-diagenetic calcite were partially reset to elevated temperatures. Taken together, these results illustrate factors that must be considered when producing environmental reconstructions from pedogenic carbonate and other terrestrial archives. These findings provide guidance on how to extract accurate paleoclimate information from paleosol carbonate and highlight the need for a process-based understanding of pedogenic carbonate formation.PHDGeologyUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttp://deepblue.lib.umich.edu/bitstream/2027.42/135835/1/tgallag_1.pd

Identification of atropine-and P2X1 receptor antagonist-reistant, neurogenic contractions of the urinary bladder

Acetylcholine and ATP are excitatory cotransmitters in parasympathetic nerves. We used P2X1 receptor antagonists to further characterize the purinergic component of neurotransmission in isolated detrusor muscle of guinea pig urinary bladder. In the presence of atropine (1 μm) and prazosin (100 nm), pyridoxalphosphate-6-azophenyl-2′,4′-disulfonic acid (PPADS) (0.1–100 μm) and suramin (1–300 μm) inhibited contractions evoked by 4 Hz nerve stimulation in a concentration-dependent manner (IC50 of 6.9 and 13.4 μm, respectively). Maximum inhibition was 50–60%, which was unaffected by coadministration of the ectonucleotidase inhibitor ARL67156 (6-N,N-diethyl-d-β,γ-dibromomethyleneATP) (100 μm). The remaining responses were abolished by tetrodotoxin (1 μm). PPADS and suramin also reduced contractions to exogenous ATP (300 μm) by 40–50%, but abolished those to the P2X1 agonist α,β-methyleneATP (α,β-meATP) (1 μm). The P2X1 antagonists reactive blue 2, NF279 (8,8′-[carbonylbis(imino-4,1-phenylenecarbonylimino-4,1-phenylenecarbonylimino)] bis-1,3,5-naphthalenetrisulfonic acid), MRS2159 (pyridoxal-α5-phosphate-6-phenylazo-4′-carboxylic acid) (100 μm), and NF449 [4,4′,4,4-(carbonylbis(imino-5,1,3-benzenetriylbis(carbonylimino)))tetrakis-benzene-1,3-disulfonic acid] (3 μm) abolished contractions to α,β-meATP (1 μm; n = 4–5), but only reduced contractions evoked by 4 Hz nerve stimulation by ∼40–60% (n = 4–6) and ATP by 30–60% (n = 4–7). However, prolonged exposure to α,β-meATP (50 μm) abolished contractions evoked by all three stimuli (n = 5–12). PPADS (100 μm) and suramin (300 μm) reduced the peak neurogenic contraction of the mouse urinary bladder to 30–40% of control. At the same concentrations, the P2X1 antagonists abolished the nonadrenergic, purinergic component of neurogenic contractions in the guinea pig vas deferens (n = 4–5). Thus, P2X1 receptor antagonists inhibit, but do not abolish, the noncholinergic component of neurogenic contractions of guinea pig and mouse urinary bladder, indicating a second mode of action of neuronally released ATP. This has important implications for treatment of dysfunctional urinary bladder, for which this atropine- and P2X1 antagonist-resistant site represents a novel therapeutic target

03-06 "Free Trade, Corn, and the Environment: Environmental Impacts of US – Mexico Corn Trade Under NAFTA"

The North American Free Trade Agreement (NAFTA) had a profound impact on corn trade between the United States and Mexico. Negotiated tariff reductions and the Mexican government’s decision not to charge some tariffs to which it was entitled resulted in a doubling of US corn exports to Mexico. This paper examines the environmental implications of this change on both sides of the border.

Prize Volatility and Presence or Absence of Anticipatory Sitmulus Signally Reward as Predictors of Electronic Game Machine Behaviour of Gamblers

This study investigated the effect of changes in prize volatility and presence or absence of an anticipatory stimulus signally reward on verbal ratings, playing behaviour, and biometric responses in casual and frequent electronic gaming machine (EGM) players. Biometric measurements of 129 participants were recorded while they played an actual EGM with money provided by the experimenters. However, only the data from 95 participants were analysed. Participants were first connected to biometric sensors to record their heart rate and galvanic skin responses, and completed a demographic questionnaire. All participants then played an EGM game for 10 minutes. After playing the EGM game, they either played the same EGM game or a different EGM game for another 10 minutes in accord with their experimental condition. The second game was characterized by one of four conditions, (a) low volatility, absence of anticipatory stimulus, (b) low volatility, presence of anticipatory stimulus, (c) high volatility, absence of anticipatory stimulus, and (d) high volatility, presence of anticipatory stimulus. After 20 minutes of EGM play, participants completed the Canadian Problem Gambling Index (CPGI; Ferris & Wynne, 2001). Statistical results revealed that the volatility condition had a significant effect on how quickly a player would bet. That is, players bet later in conditions with higher volatility. Furthermore, frequent players bet later than casual players. There was a significant interaction between volatility and player type, but the anticipatory stimulus condition was not found to have a significant effect on playing behaviour

Designing Learning Analytics Dashboards for Digital Learning Environments: Investigating Learner Preferences, Usage, and Self-Efficacy

This dissertation, a product of the European Union's CHARMING project, investigates the intersection of technology and learning, focusing on the design of learning analytics for lifelong learning. It emphasizes the importance of effective learning design and the innovative use of technology in digital learning environments. Chapter 1 presents the problem statement, highlighting the knowledge gap related to learning analytics design and the overarching research question: How does learning analytics dashboard (LAD) design influence learner preferences, interaction, and self-efficacy in training and education? Chapter 2 investigates workplace learner preferences for LADs designed for different phases of the self-regulated learning (SRL) cycle. The study reveals a preference for progress reference frames before and after task performance, while social reference frames are least preferred. Chapter 3 examines the impact of LADs with progress and social reference frames on occupational self-efficacy in virtual reality simulation-based training environments. The findings suggest that both reference frames could elicit equal change in self-efficacy, with social reference frames potentially inducing more significant change. Chapter 4 analyzes log-file data to understand chemical plant employees' engagement with LADs. The results indicate that progress reference frames might foster mastery goal orientation behaviors, while social reference frames seem to promote performance goal orientation behaviors. Chapter 5 investigates the impact of LAD reference frame type and direction of comparison on academic self-efficacy among university students. The findings highlight the influence of both comparison type and direction on changes in academic self-efficacy. Chapter 6 discusses the main research findings, theoretical and practical implications, limitations, and future research opportunities. The dissertation contributes to the understanding of LAD design and its influence on learning-related variables, providing valuable insights for educational stakeholders and researchers. This dissertation advances the understanding of learning analytics dashboard design and its impact on learner preferences, interaction, and self-efficacy in various educational contexts. The findings provide a foundation for future research and the development of more effective digital learning environments